Milk and cream testing apparatus



En GRAY AND J. c.V BICKLEY.

MILK lAND CREAM TESTING PPARATUS. APPLICATION FILED NGV. 291 1920.

Patented NOV. 15, 1921.

L UNITED s'rA'rEsPA'rrN'r oFF-ica.

EUGENE Gaaf AND #TAXES c. rrCKLEY, or sroucurrou,` WIsQoNSIN; SAlD mqxnmg. n s n s .s AssIeNoa To SAID GRAY, i i

provementsin apparatus `for testing milk and cream, particularly for the purpose of` 1 r specificgravityof milk or cream or atmix 'HILK AND CREAM TESTING APPAaA'rUs.

Jaime C; BIGKLEY, both citizens o the UnitedStates, and both residing at Stough` ton,infthe `county of Dane and State of i "Wisconsln,y have mvented certain new and useful Improvements in Milk `and Cream Testing Apparatus, of which the following isa specification. H i 1 `The present `invention has to dowith imascertaining the "contents of butter fat. The inventionhas reference to an ap aratus which `will indicatethe percentage o butter fat by a direct and `simple indication `and Without the necessity of going through any extended or"complicated calculations or operations.

W have discovelredithe fact that the turethereof ata certain determined temper-V ature will give a very accurate indication of thepercentage of butter fat present therein,

`the lower the: specific gravity/,the higher the? percentage of butter fat. `We have also foundthat in` order fto make use of thev specific gravity forthis purpose `and in order to getan vaccurate indlcation, it is desirable that `thetestl be performed at altemperature i ".of approximately `64",Fah., since it is found t that at other temperatures certain re-actions occur whichso` change the compositionithat u the specific gravity nolonger givesan accurate indicatinlofthe butter fat content.` 11` .i Thisdiscoveryliasmade it possible for us to ascertain the butterfat` content in avery direct and simplemanneryandby the use of i very?` simple apparatusbut the use of this a paratus is also associated Withthe fact `t at the tem erature of the liquid must be correct in or er to secure accurate results.

y One of the objects ofthe present invention is to provide `a very simple apparatus for f tremely simple apparatus `and one which is so arranged that 1t does not require any particular skill or training onthe part of the user in order to secure accurateresults, be-

yond the ability to read temperatures and iigures correctly. t

Other objects and uses of the invention Specication of Letters Patent.

Patented Nov. 15, 1921,

i Applicationl led November 29, 1920. Serial No. 426,894.

will appear from a detailed description of the same which consists in the features of construction and combinations of parts hereinafter `described and claimed.

Referring tovthe drawing:

`Fi urel shows a testing instrument emb odying the features of the present inventionasthe `same maybe usedin a simple type ofbottle;` i

Fig-.f2 shows a face view of a graduation card `or index for indicatingthe percentage ofiutter fatin mixtures of milk and cream; an i i Fig. 3 shows a similarl card orscale for use in an instrument" forvtesting the butter fat of milk from which a large percentage of the creamhas already been eliminated.

i Since the testing oi' butter fat content is performed by ascertaining the specific gravity of the liquid at a certain tempera.-` ture and from a knowledge of butterfat content Which corresponds to such specific gravityyit is possible to provide-a specific gravity meter which will give a direct read-` ing of :butter fat content.f This we have done inthe arrangement illustrated in the numeral 4, and adapted to set bodily into the liquid, in combination with a scale 5 of suit able markings to directly indicate the butter fat content provided the temperature of the liquid is correct.

The hydrometer is provided on its lower endwith a weight bulb 6,and on its upper end swith a tubular stem 7 into which the graduation card is placed. i The indications on this scale are so proportioned to each otherxandto the hydrometer, that the scale marking at the point Where the stem breaks through the surface of the liquid is the correct reading of the butter fat content. Ordinarily the upper end 8 of the stem is sealed after the scale has been set in place.

In Flu'. 2, we have shown a scale laid out flat, in the manner in which a sheet of paper i or pasteboard might be printed or marked as a scale for use in the testing of liquids containing a considerable percentage of cream, as for example milk fresh from the cow. .The right hand side of the scale carries a column or row ofnumerals 8 which designate percentage of butter fat for the particular hydrometer when used at a temperature of 64 Fah. The numerals of this in order to secureaccurate results.

theless, the presence of this mark 1s not scale read upward, commencing at the lower end; since the specific gravity is highest for pure skimmed milk which also contains no butter fat. We have therefore designated the lower endof theseale with the letter S shown at the point 9, which letter designates. skimmed milk. At the point l0 which' is the level at which the hydrometer scale will stand in line with the surface of a liquid of specific gravity equal to that of water, we have provided a marking W as shown at 11, the same designating the position at which the scale should stand in a water bath ofv 64 Fah.V

Experiment has `also determined the fact that when the specific gravity of a milk or cream.` mixture at 64 Fah. is unity or the same aswater, its butter fat content is 3l percentage by weight; 'and we' have therefore placed the numeral 3l at the line 10 which-.is the water line, since if the mixture of milk and cream isvsu'ch as to make the hydrometer stand at this level and is 64 Fah., it contains l-percentage butter fat.

Between thelines .designated S and W, we place. .the scale markings reading in uniform manner V4upV to 31,'andwe prefer to carry these markings on up to approximately 36 Aor 37as shown in Fig. 2, since the richest cream which will probably ever be tested in thismanner. will not contain more than 36 or 37butter fat by weight at 64 Fah.

4The vscale shown in Fig. .3 is similar to that of. Fig. `2 with the exception that it is intended for" use in a hydromet'er more specially vadapted for vthe testing of milk ifromywhicha considerable portion of cream has alreadybeen removed. f Consequently the-scale in Fig. 3 has its markings widened out considerably and will give more accuratereadin-g forv the testing of butter fat content of such milk.

In the upper portion of the scale, we prefer to place atemperature indication of y64 Fall. as shown at the point 12 so as to constantly remind the user of the instrument thatthe liquid should have this temperature Neveressential to the accurate use of the instrument provided the temperature be correct.

It will be observed that in each case the scale bears such markings with respect to the hydrometer in which it is intended to be used that it gives a direct reading of butter fat content, and for this purpose takes ad vantage of the discovery which we have made in regard to the relation of specific gravity to butter fat content when the test is made at substantially 64 Fah.

It is observed that the hydrometer is shown in Fig. l as being used within a relatively large jar. lVe have lfound that if the testing jar be made too small in diameter,

the capillary action will affect the readings of the hydrometer to such an extent as to impair their accuracy. However, by proportioning the diameter of the jar at least twice as large as the diameter of the hydrometer this inaccuracy is reduced to such an extent as to become negligible.

We claim:

An instrument for the testing of the butter fat contents of sweet milk and cream, comprising a hydrometer having a lioat, a weight at thev bottom end thereof, an upstanding hollow neck, and a scale member within said neck, said scale member having marking visible through the neck and including graduations commencing with l at the lowerend and increasing in value toward the upper end, there being a mark at the position of the indication 3l showing that thisis the position assumed by the instrument in pure water of a temperature of 64 Fah. and the instrument being so proportioned that when immersed in milk of no butter fat content and having a temperature of substantially 64 Fah. it will stand with the scale at the zero position, and being so proportioned that when immersed in milk having any proportion of butter fat content and having a temperature of substantially 64 Fah. it will stand with the scale at the position to indicate the correct percent of butter fat content, substantially as described.

Y EUGENE GRAY.

JAMES C. BICKLEY. 

